The invention relates to a coolant coupling for connecting coolant lines, particularly for use in motor vehicles, having two interlockable connectors in the form of a plug on the one hand and a sleeve on the other that can being sealed off from one another by means of at least one sealing element, which connectors can be axially secured by a closure arrangement in an interlocked position.
German Published Patent Disclosure DE 35 02 424 A1 discloses a coolant coupling for motor vehicle air conditioning systems that is provided with a plug-type connection. For connecting two pipes of a coolant line, one connector is provided with a receiving piece, serving as a sleeve, which has a widened end region. The other connector is provided with an insertion piece, acting as a plug, which is insertable with a precise fit into the receiving neck. The inside wall of the receiving neck and the outer periphery of the insertion neck rest on one another. To improve the sealing action between the insertion neck and the receiving neck, encompassing sealing rings are provided between them. To enable axially securing the two joints in the interlocked position, a closure arrangement in the form of a clamping ring is provided, which is reinforced by a spiral spring acting in the circumferential direction. An axially resilient element that is compressible axially by the clamping ring and is disposed between radially outward-protruding flanges of the insertion neck and receiving neck, serves as a means of preventing relative rotation for the connectors.
U.S. Pat. No. 2,590,565 discloses a fast-action coupling for connecting pipelines, in which one connector, serving as a plug and provided with a conically widened region, is insertable into the other connector, acting as a sleeve and provided with an expanded region. The connection between the two connectors is sealed off by an elastic sealing ring, which is disposed radially between the conically widening region of the plug and the widened region of the sleeve and extends axially over virtually the entire length of the conically widened region of the plug. To secure the interlocked position, a securing ring that engages a stop collar of the plug axially from behind is provided.
German Patent Document DE 31 43 015 C2 discloses a fast-action coupling for connecting coolant lines for use in motor vehicles, in which the two connectors of the coolant lines are embodied as a plug and sleeve, respectively, and can be interlocked axially. The plug is provided with a conically widening collar. The sleeve is widened cylindrically compared with the diameter of the plug. To avoid galvanic corrosion, the plug and sleeve are interlocked in a radially spaced-apart manner, by the interposition of a spacer, an elastic sealing ring and a bush. The bush and the spacer serve to guide and support the plug in the sleeve, to stabilize the connection between the two coolant lines; this sealing ring serves to seal off the connection of the two connectors. Like the sealing ring, which is made of an elastomer, the bush and the spacer are produced from electrically nonconductive material.
An object of the invention is to provide a coolant coupling of the type referred to at the outset that is simple and reliable to assemble and that by simple means assures secure sealing action and a stable connection between the coolant lines.
This object is attained by providing an annular combination element of a nonconductive material between the plug and the sleeve, which combination element keeps the plug radially centered and axially positioned in the sleeve, without contact between the plug and sleeve, and essentially positively fills up the annular space over the insertion length of the plug and the sleeve in order to stably support the plug in the sleeve, and in which combination element the at least one sealing element is integrated. As sealing elements, sealing rings embodied as O-rings, encompassing sealing lips, and sealing ligaments are provided in particular. As a result, the combination element is merely a single component, yet in which three essential functions are combined. First, the combination element serves to seal off the connection between the coolant lines, and the disposition of the plug in the sleeve attains a sealing action that remains the same over the entire circumference. The integration of sealing elements with the combination element means that the sealing elements are connected as separate elements with the combination element in a force locking and/or form locking manner. By the placement or inclusion of the sealing elements in suitable indentations or annular grooves of the combination element, or by already integrally forming the sealing elements onto the combination element when it is produced, particularly by injection molding or the like, a secure integration of the combination element and sealing elements is achieved. Because the nonconductive combination element keeps the plug in the sleeve without its touching the sleeve, corrosion in the case of metal joints is effectively avoided. In addition to the sealing action and centering action, the combination element also has a support function for the coupling, since it essentially positively fills up the annular space over the insertion length of the plug and sleeve. This supporting action produces a compact, stable connection between the two coolant lines, and as a result strains during motor vehicle travel can also be absorbed by the coolant coupling, without a change in the positioning of the plug and sleeve relative to one another that could cause impaired sealing action.
Contact corrosion is effectively avoided thereby, particularly in the case of metal pipes. In contrast to the prior art, only a single component, namely the combination element, is provided, while in the prior art exemplified by German Patent Document DE 31 43 015 C2, three different elements are necessary to achieve adequate sealing and supporting action, namely the spacer, the sealing ring and the bush. In the preferred embodiments according to the invention, simple and fast assembly are attained, with high accuracy and stability of the resultant connection. The coolant coupling according to the invention is therefore particularly suitable for air conditioning systems in the engine compartment of motor vehicles, in which relatively high strains are exerted on the coolant coupling when the vehicle is in operation.
In certain preferred embodiments of the invention, the annular combination element is made of plastic, can be fitted lockingly and tightly on its outer periphery into a receiving region of the sleeve, and is provided on its inside periphery with at least two encompassing sealing elements that are axially offset from one another. In various exemplary embodiments of the invention, the positive (or form locking), tight fitting into the receiving region of the sleeve is done by gluing, press-fitting, or insertion, in combination with the provision of encompassing sealing rings or sealing lips on the outer circumference of the combination element that assure a tight, positive seat in the sleeve.
By the disposition of two encompassing sealing elements on the inside circumference of the annular combination element, axially spaced apart from one another, improved equalization of tolerances is possible, compared with only one sealing element, and as a result, secure sealing action is attained.
In a further feature of the preferred embodiments of invention, the closure arrangement is provided with a closure ring held axially positively on the sleeve, a closure clamp is bound in captive fashion in the ring; this clamp can be radially spread apart for the sake of axial insertion and removal of the plug, and it positively locks the plug axially in the sleeve in the interlocked position. It is therefore possible for two connectors, inserted one in the other as a plug and sleeve, of two coolant lines to be secured in the interlocked position and locked there. Loosening of the connection is reliably avoided thereby. It is assured that the closure clamp cannot be lost even after disassembly, and thus the closure arrangement is functional at all times.
In a further feature of preferred embodiments of the invention, the closure clamp is embodied as a spring that is provided with a closed cross section and that in the assembled state encompasses the plug, the spring being supported on an inside wall of the closure ring and having at least one engagement element, accessible from an outside of the closure ring, for loosening the closure clamp. The closure clamp is accordingly retained in captive fashion in the closure ring in both the assembled and disassembled state of the closure ring, and from its position in which it axially engages the plug from behind it can be spread apart in a simple way from the outside of the closure ring, by engaging the applicable engagement element with a hand or a tool, far enough that the plug is released in the axial direction.
In a further feature of preferred embodiments of the invention, as the engagement elements, two engagement protrusions are provided on two opposed sides of the spring ring, which protrusions protrude radially to the outside through the wall of the closure ring. As a result, the engagement protrusions are pressed radially inward in a simple way from the two opposed sides of the closure ring, and as a result the connection between the two joints is loosened. In a further feature of the invention, a half-shell-like disassembly tool is provided, which can be seated on the closure ring and which for loosening the spring is provided with two cams protruding radially inward at the height of the engagement protrusions. When the disassembly tool is seated on the closure ring, the two cams press into the opening of the closure ring for the engagement protrusions, and as a result the engagement protrusions are pressed inward. By the spreading apart of the spring, the connection between the plug and sleeve is loosened in a simple way.
In a further feature of preferred embodiments of the invention, the disassembly tool is provided with a collarlike guard edge for positive axial securing of the plug during disassembly, which edge protrudes radially inward to beyond the radial height of a plug collar of the plug and which in the seated state, is disposed with axial spacing from the plug collar. In operation, coolant lines are under high pressure. When the coolant coupling is disassembled, in order to avoid having the plug pressed suddenly axially rearward in an uncontrolled fashion by the high pressure in the coolant lines after the closure clamp is loosened, the guard edge is provided, which catches the plug and keeps it in a loosened position relative to the sleeve.
In a further feature of preferred embodiments of the invention, the axial spacing is less than the axial length of the combination element. This assures that the plug will be kept positioned in the region of the sleeve even after being loosened.
In a further feature of preferred embodiments of the invention, the two half-shells are pivotably joined together on one side by means of a hinge connection, and on the opposite side they can be annularly closed by means of a detent connection. As a result, the two half-shells can be slipped over the sleeve in the folded-open position and pressed together, so that they fit over the sleeve. Disassembly is done in reverse fashion.
In a further feature of preferred embodiments of the invention, the hinge connection has at least two detent elements which can lock in detent fashion positively with one another and are pivotable relative to one another, one being disposed on the one and the other being disposed on the other half-shell. This creates a hinge clip connection that is simple to produce and that enables fast assembly and disassembly.
In a further feature of preferred embodiments of the invention the closure clamp is embodied as an essentially U-shaped, elastically spreadable bail. The closure clamp is held in the closure ring in the assembled stage so that it can be radially spread apart in a radial plane to a center longitudinal axis of the coolant coupling; the amount of spreadability is equivalent to at least the maximum diameter of the plug. When the plug is thrust into the sleeve, a suitably conically widened portion of the plug therefore presses the closure clamp apart until, behind the collar of this widened portion, it snaps back inward again and axially secures the plug. This enables one-handed assembly; in other words, the coolant coupling can be put together by robot assembly.
In a further feature of preferred embodiments of the invention, the U-shaped bail is provided with an outward bulge serving as an engagement face for a tool. By means of a suitable tool, the closure clamp can therefore be removed with a fast manual operation.
In a further feature of preferred embodiments of the invention, the closure clamp is retained in countersunk fashion in the closure ring, and the free ends of the U-shaped bail of the closure clamp are accessible by means of a tool through two openings in the closure ring. This prevents unauthorized loosening of the closure clamp, because the clamp cannot be accessed or disassembled except with a tool.
In a further feature of preferred embodiments of the invention, the closure arrangement has a positive relative-rotation-preventing means, for connecting the plug and sleeve in a defined position. In a simple way, protrusions and grooves that engage one another accordingly are provided on the closure ring and on the associated collar of the plug or sleeve.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.